The transport of Galactic cosmic rays (CRs) is likely due to an interplay between self-generated and extrinsic magnetic turbulence.
In particular, close to their sources and close to the Galactic disk, CR diffusion is likely enhanced by the large CR currents that drive the streaming instability.
We investigate the onset of the resonant and non-resonant streaming instabilities and their influence on CR transport by performing self-consistent hybrid particle-in-cell simulations.
On Galactic scales, we study how the self-generated diffusion coefficient is expected to vary from the disk to the halo, which might be crucial for both CR confinement and for providing sub-grid models in models of galaxy evolution that include CR physics.